<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>控制div属性</title>
    <script>
        var changeStyle = function (elem, attr, value) {
            elem.style[attr] = value
        };
        window.onload = function () {
            var oBtn = document.getElementsByTagName("input");
            var oDiv = document.getElementById("div1");
            var oAtt = ["width", "height", "background", "display", "display"];
            var oVal = ["200px", "200px", "red", "none", "block"];

            for (var i = 0; i < oBtn.length; i++) {
                oBtn[i].index = i;
                oBtn[i].onclick = function () {
                    this.index == oBtn.length - 1 && (oDiv.style.cssText = "");
                    changeStyle(oDiv, oAtt[this.index], oVal[this.index])
                }
            }
        };
    </script>
    <style>
        .bt-wrap {
            width: 500px;
            margin: 0 auto;
            padding: 0;
            text-align: center;
        }

        #div1 {
            width: 100px;
            height: 100px;
            background-color: #000;
            display: block;
            margin: 10px auto;
        }
    </style>
</head>

<body>
    <div class="bt-wrap">
        <input onclick="changeWidth()" type="button" value="变宽">
        <input type="button" value="变高">
        <input type="button" value="变色">
        <input type="button" value="隐藏">
        <input type="button" value="重置">
        <div id="div1"></div>
    </div>
</body>

</html>